There is a growing demand in the radio communications system market to reduce the size of radio communication sites. A radio communication site typically comprises an antenna structure and a base station structure. The base station structure typically houses communications equipment. For example, in cellular radio communications systems, the communications equipment typically consists of a radio transceiver, a digital controller for site management, a power supply and backhaul equipment to carry data and traffic to and from a network controller located away from the communication site. The base station structure typically adjoins the antenna structure or is located very near to the antenna structure. A cable connects the antenna with the radio transceiver in the base station structure.
Many radio communication sites are costly to install and require a substantial amount of real estate to be purchased or leased. Many radio communication sites are also costly and difficult to maintain especially when dealing with components of the antenna structures which are located near the top of the antenna structures (e.g. antennas, preamplifiers, etc.).
The base station structures typically require expensive heating and cooling systems to maintain proper environmental conditions for the communications equipment. Furthermore, the base station structures are typically "vandal proofed". The vandal proofing and the heating and cooling systems add to the cost of a radio communication site. In addition, the requirement for heating and cooling systems reduces the reliability of the communications equipment.
Furthermore, especially at VHF and UHF frequencies, there is typically a great deal of transmission loss in the cable that connects the antenna with the radio transceiver housed in the base station structure. Consequently, a larger radio transceiver with a higher power output is typically required to compensate for the transmission loss in the cable. Since the larger radio transceiver typically generates more heat, a larger cooling system is typically required. The larger radio transceiver and the larger cooling system add to the cost of the radio communication site.
Moreover, many radio communication sites create visual clutter and are not very aesthetically appealing. For example, in cellular radio communication systems, many antenna structures use lattice towers. The base station structures typically use environmentally controlled huts, 400 to 800 square feet in size. Both the base station structures and the antenna structures are typically surrounded by chain link and razor wire fencing.
Not surprisingly, due the scale and visual clutter of many proposed radio communication sites, service providers often experience strong community resistance to the erection of these proposed radio communication sites. The strong community resistance often creates delays for the service provider and may even cause the cancellation of necessary governmental permits for the proposed radio communication sites.
U.K. patent application 2,289,827 published on Nov. 29, 1995 in the name of Vernon Julian Fernandes as inventor, discloses an integrated base station and antenna mast. In an attempt to address some of the problems mentioned above, the communications equipment (including radio transceivers) is housed inside a hollow mast. Consequently, the need for a separate base station structure is eliminated. Convenient means to cool the communications equipment is provided by internal convection, conduction through the body of the mast and radiation. However, the U.K. patent application does not address the high cost of maintaining communication sites which have components, such as antennas and RF modules (or radio transceivers), located near the top of the antenna structure, nor does it address the transmission losses in the cable connecting the radio transceiver with the antenna.